With the development of wireless multimedia services, people have an increasing demand for high data rate and good user experience, and raise a higher demand for system capacity and coverage of a conventional cellular network. In a conventional Long Term Evolution (LTE) cellular network, a Macrocell serving as a unique access side network element provides an access service for User Equipment (UE). However, to meet the demand of a user for higher data rate and to improve the spectral efficiency of the cellular network, a 3rd Generation Partnership Project (3GPP) introduces a Small Cell (SC) or a Small Cell Enhancement (SCE); the SC serving as a supplement of a Macro evolved NodeB (eNB) provides an access service for the UE. The SC originates from a Femtocell initially designed for a family scene; the small cell is relatively small with respect to a conventional Macro eNB, and has the characteristics: miniaturization, low-emission power, high controllability, intelligence and flexibility in networking. With respect to the emission power, the typical emission power of the small cell is between 100 mW and 5 W; with respect to the weight, the general weight of the small cell is between 2 kg and 10 kg; with respect to a networking mode, the small cell supports backhaul in various technologies including Digital Subscriber Line (DSL), optical fibre, Wireless Local Area Network (WLAN) and cellular technology, and further has self-organization and self-optimization functions such as automatic neighbouring cell discovering, self-configuration and the like.
The small cell has four types of product forms: the first one is called Femtocell, which is mainly applied to family and enterprise environments; the second one is called Picocell, which is applied to indoor public places such as an airport, a train station and a shopping centre; the third one is called Microcell, which is applied to downtowns where a Macro eNB cannot be deployed due to limited spaces, or villages; the last one is called Metrocell, which is mainly applied to hot spot regions in downtowns to reduce the capacity bottleneck, or applied to villages. As shown in FIG. 1, the environment of a small cell network is very complicated, and its quantity of eNB equipment of the small cell is orders of magnitude more than that of a conventional Macro eNB network.
Since September 2007 when the Sprint, the first one in the world, deploys Femtocell, small cells have been successfully deployed in forty-one networks of twenty-three nations; at present, more than 3,800,000 small cells have been deployed in the whole world mainly in the form of Femtocells (80%). However, from regional distribution, the small cells have been mainly distributed in America (the Sprint has deployed more than 900,000 small cells/the AT&T has deployed about 500,000 small cells), Europe, Japan and South Korea (there are 120,000 small cells deployed by the Softbank of Japan).
Under a hot-spot deployment scene, to achieve higher data rate and higher spectral efficiency, a large number of small evolved NodeBs (eNBs) are required to be concentrated in a region; in addition, a Macro eNB and the small eNBs may adopt different frequency points, and the small eNBs may probably adopt different frequency points. Particularly, in an indoor deployment scene, such as offices, malls and the like which are generally built in multi-floor buildings, different floors probably have small eNBs, and the working carrier frequencies of the small eNBs on different floors are probably different.
Under the environment of a home eNB, when there is no user accessing or a load is extremely low, the home eNB can fulfil the aim of saving energy by moving a user out of a cell and then closing the emission power of the cell or the eNB. Further, appropriate awakening of a cell of the home eNB is implemented by means of reporting of Proximity Indication (PI) information of UE. Under the environment of a small cell, since the small cell in an energy saving mode may be switched out or shut down the carrier wave emission power, even if the UE reports the PI information of the small cell, a measurement result cannot be reported unless the network side transmits a measurement control command after the small cell is awakened, and then the reporting of the measurement result enables the small cell to provide a normal service for the UE. At the present, some of mechanisms enable UE in an energy saving state to discover a small cell in the energy saving state; for example, by virtue of the design of a small cell discovering signal, the UE can sense information that the small cell is in the energy saving state; the UE can configure energy saving indication information (which indicates that the Small Cell is in the energy saving state), and report it to an eNB where a current serving cell is located. On the other hand, due to individual particularities of single and multiple users, when the capacity of a current network is limited, the small cells in the energy saving state are required to be awakened timely to provide services for the users. Therefore, how to enable the network side to accurately determine an appropriate target small cell to be awakened through information reported by the UE to avoid unnecessary awakening operation on an interface is a problem to be solved in an existing network.